1. Field of the Invention
The present invention relates to a hyperlink having a time dependency and related to a video.
2. Description of the Related Art
Hypertext systems, such as the World Wide Web (WWW), contain objects, i.e. electronic documents, which are creatively linked to each other. During a session, a user device is connected via a browser to a content server including an object and content is exchanged between the user device and the content server. The exchange of content occurs over the internet using, for example, a hypertext transport protocol (HTTP) for hypertext documents. The HTTP protocol messages are carried in Transmission Control Protocol/Internet Protocol (TCP/IP) messages. It is also possible to transmit voice or video content over the internet. For the establishment of voice and/or video multimedia session protocols like Session Initiation Protocol (SIP) and H.323 are used. Multimedia sessions can be established via SIP by selecting links from HTTP hypertext documents, if the browser is equipped with multimedia capabilities. SIP is a client-server protocol in which requests are generated by one entity (the user or client) and sent to a receiving entity (the server). Contacting the server of the new object may be accomplished by looking up the domain name of the new server in a Domain Name Service (DNS) and determining the correct IP address. The DNS is actually its own network. If one DNS server does not know how to translate a domain name, it asks another, and so one, until the correct IP address is found. The request from the browser is sent to the IP address and may be redirected to where the actual object is connected. The object returns a response through the chain.
Each object which the user device may access may include one or more hyperlinks that link to another place in the same document or to an entirely different object. The hyperlinks occur within a certain area in the object and may include a picture or phrase, a word, an icon, or any other visual representations. The hyperlinks in these objects may be selected by clicking when the cursor is within the area of the hyperlink. When the hyperlink is selected, the browser of the user device switches over to a new object that is associated with the hyperlink.
Prior art video content include hyperlinks and other WWW type content associated with video programs. However, the hyperlinks and WWW type content that are associated with prior art video content are transmitted in parallel to the video program without being associated directly to spatial objects within the video stream. Therefore, these hyperlinks are not bound to objects in the video. It is desireable to navigate in video/multimedia content using hyperlinks bound to the video content. Similarly, the prior art does not define mechanisms for implementing a seamless switchover between video contents. In the prior art, there is always an observable delay when establishing a new session after a hyperlink has been selected from, e.g., a web page displayed by the side of a television picture.
Furthermore, in the prior art, there are no mechanisms having parallel multimedia streams active for potential switchover periods while retaining only one multimedia stream toward the user device.